To Love Him True
by Goddess-of-the-Night04
Summary: Sherlock Holmes - Potions Experimenter Extraordinaire - combines Amortentia with Veritaserum to help users not only find their true love, but to express that love. In hindsight, maybe he shouldn't have tested it on himself. (Potterlock - but no Harry Potter characters are involved or mentioned. Basically just John and Sherlock playing around at Hogwarts)


**Disclaimer:** I own no part of the BBC Sherlock or Harry Potter worlds and am making no profit from this.

 **A/N:** Harry Potter was the first fandom I wrote for and Sherlock the second. I find myself adoring much of the Potterlock world, but hate that there's just not enough of it.

So here's my first foray in to it...possibly my last, but I never quite know where my muse is going to take me.

* * *

Your average seventh year at Hogwarts typically spends their evenings studying with their friends until extremely late, then goes to bed once their tears have abated. Graduation is nearly upon them, and they could never have even dreamed this stress level up. It makes their fifth year OWL prep seem mild.

For Gryffindor John Watson and Ravenclaw Sherlock Holmes, this means that they spend most nights - just the two of them - studying in the library together before John heads to bed and Sherlock returns to his potions experiments.

John is Sherlock's only friend, not only because Sherlock tends to rub people the wrong way by making observations about them that they'd rather he wouldn't, but because he strongly believes he only needs one friend. He probably wouldn't even have conceded to _that_ if John hadn't been so different from the rest of the children he had ever met.

John, on the other hand, is a bit more social by nature, but mostly he's just a people pleaser. He wants to be a medi-wizard, and he is charismatic enough to do so, but he honestly envies Sherlock a little. Sherlock is so confident in who he is that he can't be bothered if anyone really likes him, he's brilliant enough at what he does that people still begrudgingly admit that he's right.

At nearly two o'clock in the morning - after one such night of studying John had seen to his Headboy duties before going to bed - Sherlock finds himself alone in an empty classroom he commandeered two years ago for his experiments. He works on them mostly in the early hours; because he tends not to sleep for days on end, he finds this an appropriate use of his time.

He's been working on a potion for the last couple of months that combines amortentia and veritaserum. The main goal of the mixture is to aid those in honestly finding their true love versus creating false feelings. The amortentia will help the user to discover those smells associated with the one they love, and the veritaserum will force them to be truthful about it.

He did not, however, anticipate the uncontrollable urge the drinker would have to immediately go and profess said feelings to their heart's desire.

If he had known that, he would have paid a younger student to test the potion, as he usually does, instead of drinking it himself. But the truth is that he's never been in love - isn't even certain what it's supposed to _be_ like - and has been desperate to know if what he feels when he's both near and far from his only friend is this fabled thing they call love.

The fact that he's standing outside the door of John's single room at 2:30 in the morning, drawn there by the potion, is undeniable proof.

John answers the insistent knocking, apparently fully awake even though he only just fell in to a true sleep.

"Sherlock?" He asks, confused, as he tries to slow his heart down. From the intense knocking, he thought someone was dying.

"You will make an excellent medi-wizard with your ability to be so coherent immediately after waking."

"What?" John asks for lack of anything else processing, "Are you alright?"

"Yes," he answers.

John finally looks at him - _really_ looks at him - and notices the trance-like state Sherlock is in. His worry grows, "What are you doing here?"

"I came to tell you that I'm in love with you," he answers simply.

"I…what?" John tries to process the situation.

"I love you," he repeats, just as easily. Behind the bit of glazed-over calmness, Sherlock is freaking out. The veritaserum is potent enough to get him to only speak truths, but is diluted enough that he can still register what is happening. He will remember everything.

John sees the trace of panic behind the falsely calm eyes and knows that something beyond Sherlock's control is at work. He pushes aside the rush of joy at hearing those words coming from his friend whom he has been pretending not to have feelings for - because Sherlock has always proclaimed that dating is not his area - and brings his clinical side to the forefront.

"I think you should come in," John says, stepping back from the door and allowing his best friend to enter. He can't help but look around the common room quickly to see if anyone witnessed the display, pleased to see the area deserted. He closes the door.

Sherlock is standing in the middle of the room, so John tells him to sit in the desk chair as he seats himself on the edge of his own bed. For a few long minutes they simply stare at each other - John is trying to think of how to start the conversation, and Sherlock is desperately trying to stop himself from confessing anything else.

"So…you're clearly under a spell or potion," John starts slowly, logically, "Tell me what it is," he orders, having put two-and-two together to realize that veritaserum is somehow involved.

"One of my experiments that doesn't yet have a name," Sherlock answers, then adds, "May not ever have a name; this is unbearable."

John groans and closes his eyes as his chin falls to his chest. He had begged Sherlock to stop experimenting on himself and first years - to ask Professor Northup for help on how to get them tested legally - but he just won't listen to reason. His way is faster, and with how quickly Sherlock can move from one idea to the next, he needs to have them tested as soon as possible. One of these days Sherlock is going to invent a potion that is life-altering, and John doesn't want to see it never be realized simply because Sherlock got bored by waiting around for the testing phase to be done properly.

"What were you working on?" John asks, trying to push his frustration down.

"A mix of amortentia and veritaserum."

John's eyebrows shoot upwards at the answer, "A love and truth potion? But you despise love!" he says without thinking it through.

"I do not _despise_ love," Sherlock corrects, "I just never thought I would experience it myself."

"So why were you mixing the two?"

"Curiosity. And to improve the love potion."

"Improve it how?"

"Love potions can create the feeling in anyone who takes it. It creates lies. Veritserum negates lies."

"So you wanted to create a love potion that what? Makes you realize and face the one you love instead of letting you falsely love just anyone?"

Sherlock's head tilts in innocent confusion, asking a question of his own, "What is the point of pretending to love someone that you don't? When my potion wears off, the truth is still there: that I love you. It isn't the potion making the feeling, it's the potion making me _face_ the feeling."

John's face flushes in embarrassment. So Sherlock _does_ really love him. That's…a good thing. Great, actually. But a bit of him twinges with sadness that it happened this way.

"Why couldn't you just tell me?" He asks, trying to cover the sadness.

"I didn't know for sure," he admits.

This shocks John. He's known for years that he's in love with Sherlock, he just kept tamping it down because Sherlock's not in to that sort of thing. He'd rather have him as a best friend than nothing at all, "You didn't _know_ you're in love with me?" He asks incredulously.

"I have never felt anything like what I feel for you," he admits, still with the veritaserum glazed-over look and sound.

"Oh," John says quietly before looking at the floor. He can feel Sherlock's eyes still on him, but can't bring himself to meet the mostly empty eyes.

"Are you not going to say it back?" Sherlock asks. It sounds robotic because of the potion, but the aching in his heart at the thought that his feelings aren't returned radiates through him, hatefully reminding him that he is human.

John looks back in to Sherlock's eyes sharply. He debates telling him, confessing everything: that he's loved him for years, that he's brilliant and adorable, that he has never met anyone like him, that he can't understand why he chose John over everyone to be close to…but he can't. Even if Sherlock does remember this once the potion wears off, he won't say those words now, after so long of holding them in.

"Not like this," he says quietly, his eyes portraying his sadness and apology. He hopes Sherlock can see that it isn't a refusal of the feelings, just the circumstance that he's placed them in.

"Why not?" Sherlock asks, still calm as his heart breaks.

John debates how to reassure him that he's not being rejected without actually confessing his feelings. It's difficult, "Because I want you to be you."

Sherlock's brow furrows slightly, all the potion will allow, "I _am_ me."

"No. You're not."

"John, please," he begs, neither really knowing what for.

John sighs heavily, closing his eyes and clenching his fists to restrain himself from going over to physically reassure his best friend. He opens his eyes and instead asks, "Did you clean up the classroom before you came here?"

A new topic is good. Is necessary.

"No."

"Is the fire still lit under the cauldron?"

"Yes, but it needs to be."

"I'm going to go look at the room and make sure nothing is going to burn the castle down," John says tiredly before standing from the bed.

As he reaches the door, John notices that Sherlock has stood and is following him. He turns around fully to face him, "What are you doing?"

"Going with you."

"No, Sherlock, just…stay here," he practically pleads.

"And do what?"

"Sleep," he says, knowing he can't send his friend back to his shared dorm. Not that he thinks he'll do anything untoward with the others, but because he needs to make sure he's alright through the night.

"Don't want to sleep," he negates quietly, stepping forward so that they are standing nearly chest to chest.

John can't bring himself to move backwards as his breath hitches. Doesn't _want_ to. He stands still, frightened of scaring him off, as Sherlock's right hand raises to gently run the backs of his fingers across his left cheek, but closes his eyes and leans in to the light touch. He doesn't step back as Sherlock steps forward, closing the last bit of distance separating them so that they are pressed flush from what feels like chest to toe. John's hands move to Sherlock's sides, grabbing his shirt in his fists to restrain himself while at the same time consenting to the proximity. Sherlock's right hand moves to the nape of John's neck, pulling the slightly shorter boy's face to his and pressing their right cheeks together.

For half a minute they stand just like this, breathing in unison as they relish simply being close to one another. Then Sherlock's face moves and John's heart - just recently calmed by the lack of further movement - begins to race once more. Sherlock's left hand comes up to rest on the side of John's neck, his thumb moving lightly over a particularly sensitive spot just under his ear. John shudders and presses forward in to his body without thought, but God does he want this man. John's left hand loosens its hold on Sherlock's shirt, merely resting on his too-thin side instead.

Sherlock lightly traces his lips over John's right cheek, up to his brow where he simply takes in his scent, before mirroring the tracing on the left cheek. John can't breathe, can't _think_. He has wanted this for so long, but he never imagined that his level of desire could be higher in the moment of its actualization than it is in his dreams.

As Sherlock's lips move yet closer to John's, he whispers a plea, "John."

And that's when John remembers the potion. That's when he gently pushes Sherlock away and steps back. He had no idea his will power was so strong.

"I'm sorry, Sherlock," he says truthfully, seeing the slight confusion that the potion is letting through, "Please, just lay down and rest. I'll be back soon," he promises, his heart aching at the loss as well as the bit of a blank look still on Sherlock's face from the potion.

He walks out in to the common room, not stopping his forward movement until he's outside of the portrait in the hall, too afraid of what he'll do if he stays too close to him. Sherlock says he loves him, but surely he wouldn't forgive John for taking advantage of his less-than-coherent state.

He leans against the cool stone wall and simply breathes, eyes closed tight, as he goes back over what just happened. Sherlock loves him. He can't fight the smile that appears at the thought, but he also can't help the bit of doubt since it wasn't said with his full awareness. He had pulled John close, caressed his face…nearly kissed him. A shudder of desire passes through him again just at the thought.

With a resolved notion that he will damn well kiss that boy should he still want it once his head is cleared, he pushes off the wall to find Sherlock's experiment room. He enters to find the lights on, too large a flame beneath the cauldron, and books strewn haphazardly. With a sigh he rights the chaos, lowers the flame to stasis level, and puts out the lights before leaving again.

He's tired - it being nearly 3:30am at this point - but he fears going back to his own room. What will he find? God, he hopes Sherlock didn't run off and actually stayed where he was told. That thought alone spurs him quickly back to his room to make sure.

He finds Sherlock in his bed, on his right side facing the door. He isn't asleep, but he also doesn't acknowledge John's return to the room. After a short debate, John grabs two extra blankets from his trunk, setting one on the ground before sitting with his back against the wall and the other overtop himself for warmth. In the dull light, the two stare at each other across the void.

Just as John's eyes begin to close in submission to his will to go back to sleep, Sherlock speaks up quietly.

"You can't sleep on the floor in that position."

"It's fine, Sherlock, really," John insists honestly, eyes opening again.

"Your shoulder and leg will not agree with you in the morning," he points out.

Two years ago John had injured his right leg and left shoulder in a Quidditch accident. It ended his time as a (very good) Chaser, but he didn't mind too much; he always knew he wasn't going to play Quidditch forever and the injury allowed him to start focusing more on his post-graduate plans of studying medicine.

John knows he has a valid point, but the bed isn't really suitable for two people to share it, at least not without cuddling, and he's not certain that's the best idea at the moment.

"I'll cope," he insists.

Enough time elapses in silence where John is beginning to think he's given up or finally drifted off to sleep.

"John," he starts a bit shakily, and it catches the shorter boy off-guard; it's the most emotion he's heard in his friend's voice since he woke him up, "I…it hurts to see you so close but not to be touching you," he admits, the words still being pulled from him via veritaserum, "It physically _hurts_ ," he reiterates, "So please, I know I've ruined everything, but I need you to lay with me. That's all," he promises.

John thinks the emotions being permitted to shine through means that the potion is hopefully wearing off. The pain in Sherlock's voice leads John not to hesitate before standing and moving towards the bed. He stands at the side, looking down in the wane light to simply stare at his face for a moment. It's heartbreaking and he fears he may be losing him.

John pulls the covers on the right side of the bed up so he can climb beneath them. He lays down on his back and is surprised at how quickly Sherlock curls in to him, resting his head on his left shoulder, his left hand over his heart.

"I'm sorry," Sherlock whispers brokenly.

John's arms wrap around him instinctively, protectively, "You haven't ruined _anything_ ," he stresses firmly, needing him to believe it.

"You're my friend. The only friend I've ever really had. You call me your best friend because you enjoy other people, but I detest everyone but you," he whispers, still caught up in emotion but seemingly unable to stop the truth from escaping, "You're kind and smart and so talented in so many things and you care about me, I know you do. I'm no good with emotions; my family isn't big on touchy-feely declarations of love so I haven't known…I never knew _how_ I was supposed to know…what love actually feels like."

He pauses and John's arms tighten around him as he fights tears. He knows very little about Sherlock's childhood prior to Hogwarts, but he remembers that scrawny little boy always at the same table of the library, studying books that were almost bigger than he was.

"That's why I needed to create this potion. Not to know what love feels like, but to know truthfully if what I was feeling for you was it. Well, it is and I'll tell you something I didn't expect: love bloody _hurts_ ," he says a bit disdainfully, his true demeanor shining through again little by little.

John can't help the chuckle that escapes before he agrees, "Yeah, it does, genius."

They lay in a comfortable silence, John's right hand tracing nonsensical patterns on Sherlock's left arm while Sherlock's left hand traces circles over John's heart.

"I know you have reservations because I first said it while under the effects of the potion," Sherlock whispers again, but now merely nervous versus being emotional, "but I really do love you.

John smiles at his understanding, and the feeling of hope that they may come out on the right side of this after all, "Tell me again in the morning, then."

"But…" he says in shock.

John chuckles quietly before placing a kiss to the top of Sherlock's head and saying, "Goodnight, Sherlock."

Sherlock nuzzles John's shoulder before settling on it heavily, finally relaxed enough to sleep, "Goodnight, John."

* * *

John wakes around 10 the next morning, surprised to find himself on his left side instead of his back, Sherlock still cradled strongly in his arms. He smiles to know Sherlock didn't run away in the night and sighs contentedly as he pulls him yet closer. Sherlock makes a quiet, pleased sound at the motion before returning the gesture.

It only takes a few minutes of John running his hand through Sherlock's unmanageable curls before the lankier man wakes.

When Sherlock realizes the position they're in, he scoots back just enough to look at John's face. His breath catches as his eyes portray his concern.

"Do you remember earlier this morning?" John asks gently, nervous himself.

"Yes," he admits, eyes falling to somewhere near John's arm, still wrapped around him.

"Did you mean what you said?" He asks, unable to pretend that he cares for any other information at this moment.

"I was under the effects of veritaserum, you _know_ I had to mean it," he says defensively, eyes not raising as he prepares for John to mock him.

"I know, but…" John starts nervously, biting his lip as he debates how to ask without sounding needy, "I asked you to tell me again in the morning," he settles on a reminder.

The tone of John's voice sets Sherlock's analytical mind in to action. He looks back at John's face in shock and reserved hope. Whatever he sees there leads him to repeat the words, "I love you, John."

John smiles brightly and closes his eyes briefly while he allows himself to believe the words for the first time in his life. He opens them again, "I love you, too, Sherlock."

This time, when Sherlock's lips trace timidly from his cheek to his mouth, he pulls him closer instead of pushing him away.

* * *

 **A/N:** As always, I would love to hear your thoughts via comment or constructive criticism!

Follow me on Tumblr at goddess-of-the-night04 for an easy way to keep up with any new stories from me or just to chat; I'd love hear from you :)


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